Invisible Ink Experiment Worksheet

Science experiments lesson 13: Lemon juice invisible ink · Set 685 · 40 questions

What you do (Heat shows the secret): 1. Dip a cotton bud in lemon juice and write a secret message on white paper. 2. Let the paper dry completely — the writing disappears. 3. An adult irons the paper on a low setting while you watch from a safe distance. 4. Read the brown message and wash your hands.

1. 1.🧺 Do we need turmeric powder for the secret lemon message? (a) not needed (b) needed
2. 2.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “the iron setting”? (a) we keep it the same (b) we change it (c) we measure it
3. 3.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is what we measure. (a) False (b) True
4. 4.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a balloon (b) lemon juice (c) white paper (d) a small bowl
5. 5.🧺 Which of these is not needed for the secret lemon message? (a) a small bowl (b) white paper (c) a balloon (d) a cotton bud
6. 6.📘 The browning of lemon juice with heat is a ___ change. (a) chemical (b) magnetic (c) physical (d) musical
7. 7.🔮 Predict: you write with plain water instead of lemon juice. What appears after ironing? (a) dark brown words (b) almost nothing (c) a rainbow (d) blue words
8. 8.🍋 Which of these steps is a job a child can do? (a) ironing the paper (b) reading the message (c) plugging in the iron (d) cutting the lemon
9. 9.🔍 Which is the odd one out? (a) writing the message (b) letting the paper dry (c) reading the message (d) putting the iron away
10. 10.🍋 Which of these steps is a job a child can do? (a) putting the iron away (b) cutting the lemon (c) ironing the paper (d) letting the paper dry
11. 11.🔍 Which is the odd one out? (a) putting the iron away (b) cutting the lemon (c) plugging in the iron (d) letting the paper dry
12. 12.🔍 Which is the odd one out? (a) dipping the cotton bud (b) cutting the lemon (c) plugging in the iron (d) ironing the paper
13. 13.🔍 Which is the odd one out? (a) letting the paper dry (b) cutting the lemon (c) dipping the cotton bud (d) writing the message
14. 14.🧺 Do we need an adult with an iron for the secret lemon message? (a) not needed (b) needed
15. 15.True or false: an adult with an iron is not needed for the secret lemon message. (a) False (b) True
16. 16.🍋 Which of these steps is a job for an adult? (a) reading the message (b) dipping the cotton bud (c) writing the message (d) plugging in the iron
17. 17.🔮 Can the brown writing go back to being invisible? (a) no, it stays brown (b) yes, if shaken (c) yes, in the dark (d) yes, if cooled
18. 18.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a cotton bud (c) a magnet (d) a balloon
19. 19.🍋 Secret message: who does this step — cutting the lemon? (a) an adult does it (b) a child can do it
20. 20.🛟 Why must children keep their fingers away from the iron? (a) it is magnetic (b) it is sticky (c) it can burn skin (d) it is cold
21. 21.🧺 Which of these is needed for the secret lemon message? (a) a mirror (b) a balloon (c) white paper (d) turmeric powder
22. 22.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? What do we do with “how dark the writing is”? (a) we change it (b) we measure it (c) we keep it the same
23. 23.🧺 Which of these is not needed for the secret lemon message? (a) an adult with an iron (b) a cotton bud (c) lemon juice (d) a mirror
24. 24.🧺 Which of these is needed for the secret lemon message? (a) a small bowl (b) turmeric powder (c) a battery cell (d) a balloon
25. 25.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) white paper (c) lemon juice (d) a magnet
26. 26.🍋 Which of these steps is a job for an adult? (a) dipping the cotton bud (b) reading the message (c) letting the paper dry (d) cutting the lemon
27. 27.True or false: ironing the paper is a job for an adult. (a) True (b) False
28. 28.🧺 Three of these are needed for the secret lemon message. Which one is NOT needed? (a) a small bowl (b) turmeric powder (c) white paper (d) a cotton bud
29. 29.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the iron setting is the one thing we change. (a) False (b) True
30. 30.True or false: a magnet is not needed for the secret lemon message. (a) False (b) True
31. 31.🍋 Secret message: who does this step — plugging in the iron? (a) a child can do it (b) an adult does it
32. 32.🍋 What colour does the lemon writing turn when an adult warms it? (a) white (b) green (c) brown (d) blue
33. 33.True or false: ironing the paper is a job a child can do. (a) False (b) True
34. 34.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? True or false: the ironing time is kept the same. (a) False (b) True
35. 35.🧺 Which of these is not needed for the secret lemon message? (a) a cotton bud (b) a small bowl (c) an adult with an iron (d) a battery cell
36. 36.⚖️ Fair test — does lemon juice or orange juice make darker secret writing? Which of these is the one thing we change? (a) the kind of juice (b) the ironing time (c) the iron setting (d) the same cotton bud
37. 37.🧺 Which of these is not needed for the secret lemon message? (a) yeast (b) a cotton bud (c) white paper (d) a small bowl
38. 38.True or false: a small bowl is not needed for the secret lemon message. (a) True (b) False
39. 39.True or false: white paper is not needed for the secret lemon message. (a) True (b) False
40. 40.🍋 Secret message: who does this step — writing the message? (a) an adult does it (b) a child can do it

Free science experiments lessons, practice and worksheets at talentjr.in/science-experiments-for-kids